Large-scale drivers of compounding hot and dry events in three breadbasket regions

Abstract. Compound hot and dry events cause damage to ecosystems and society. While these events have been widely studied individually, their co-ocurrence and the associated large-scale atmospheric drivers remain less understood. Here, we use reanalysis products and observational data to identify compound hot and dry events in the historical period from 1960 to 2020. We analyze the large-scale circulation patterns associated with compound occurrence of hot and dry events when they affect large portions of three breadbasket regions in the Northern Hemisphere, namely North America, Europe and the Mediterranean and eastern Asia. We find that compound hot and dry events recur throughout the historical period and are consistently linked to Rossby wave patterns and mid-tropospheric anticyclonic ridging, which trigger land-atmosphere feedbacks resulting in the reinforcement of the events. Our study highlights that the spatial extent of compound hot and dry events offers a metric for assessing regional impacts.